1 /* $OpenBSD: auth.h,v 1.108 2024/05/17 06:42:04 jsg Exp $ */ 2 3 /* 4 * Copyright (c) 2000 Markus Friedl. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 */ 27 28 #ifndef AUTH_H 29 #define AUTH_H 30 31 #include <signal.h> 32 #include <stdio.h> 33 34 #ifdef HAVE_LOGIN_CAP 35 #include <login_cap.h> 36 #endif 37 #ifdef BSD_AUTH 38 #include <bsd_auth.h> 39 #endif 40 #ifdef KRB5 41 #include <krb5.h> 42 #endif 43 44 struct passwd; 45 struct ssh; 46 struct sshbuf; 47 struct sshkey; 48 struct sshkey_cert; 49 struct sshauthopt; 50 51 typedef struct Authctxt Authctxt; 52 typedef struct Authmethod Authmethod; 53 typedef struct KbdintDevice KbdintDevice; 54 55 struct Authctxt { 56 sig_atomic_t success; 57 int authenticated; /* authenticated and alarms cancelled */ 58 int postponed; /* authentication needs another step */ 59 int valid; /* user exists and is allowed to login */ 60 int attempt; 61 int failures; 62 int server_caused_failure; 63 int force_pwchange; 64 char *user; /* username sent by the client */ 65 char *service; 66 struct passwd *pw; /* set if 'valid' */ 67 char *style; 68 69 /* Method lists for multiple authentication */ 70 char **auth_methods; /* modified from server config */ 71 u_int num_auth_methods; 72 73 /* Authentication method-specific data */ 74 void *methoddata; 75 void *kbdintctxt; 76 #ifdef BSD_AUTH 77 auth_session_t *as; 78 #endif 79 #ifdef KRB5 80 krb5_context krb5_ctx; 81 krb5_ccache krb5_fwd_ccache; 82 krb5_principal krb5_user; 83 char *krb5_ticket_file; 84 char *krb5_ccname; 85 #endif 86 struct sshbuf *loginmsg; 87 88 /* Authentication keys already used; these will be refused henceforth */ 89 struct sshkey **prev_keys; 90 u_int nprev_keys; 91 92 /* Last used key and ancillary information from active auth method */ 93 struct sshkey *auth_method_key; 94 char *auth_method_info; 95 96 /* Information exposed to session */ 97 struct sshbuf *session_info; /* Auth info for environment */ 98 }; 99 100 /* 101 * Every authentication method has to handle authentication requests for 102 * non-existing users, or for users that are not allowed to login. In this 103 * case 'valid' is set to 0, but 'user' points to the username requested by 104 * the client. 105 */ 106 107 struct authmethod_cfg { 108 const char *name; 109 const char *synonym; 110 int *enabled; 111 }; 112 113 struct Authmethod { 114 struct authmethod_cfg *cfg; 115 int (*userauth)(struct ssh *, const char *); 116 }; 117 118 /* 119 * Keyboard interactive device: 120 * init_ctx returns: non NULL upon success 121 * query returns: 0 - success, otherwise failure 122 * respond returns: 0 - success, 1 - need further interaction, 123 * otherwise - failure 124 */ 125 struct KbdintDevice 126 { 127 const char *name; 128 void* (*init_ctx)(Authctxt*); 129 int (*query)(void *ctx, char **name, char **infotxt, 130 u_int *numprompts, char ***prompts, u_int **echo_on); 131 int (*respond)(void *ctx, u_int numresp, char **responses); 132 void (*free_ctx)(void *ctx); 133 }; 134 135 int 136 auth_rhosts2(struct passwd *, const char *, const char *, const char *); 137 138 int auth_password(struct ssh *, const char *); 139 140 int hostbased_key_allowed(struct ssh *, struct passwd *, 141 const char *, char *, struct sshkey *); 142 int user_key_allowed(struct ssh *ssh, struct passwd *, struct sshkey *, 143 int, struct sshauthopt **); 144 int auth2_key_already_used(Authctxt *, const struct sshkey *); 145 146 /* 147 * Handling auth method-specific information for logging and prevention 148 * of key reuse during multiple authentication. 149 */ 150 void auth2_authctxt_reset_info(Authctxt *); 151 void auth2_record_key(Authctxt *, int, const struct sshkey *); 152 void auth2_record_info(Authctxt *authctxt, const char *, ...) 153 __attribute__((__format__ (printf, 2, 3))) 154 __attribute__((__nonnull__ (2))); 155 void auth2_update_session_info(Authctxt *, const char *, const char *); 156 157 #ifdef KRB5 158 int auth_krb5_password(Authctxt *authctxt, const char *password); 159 void krb5_cleanup_proc(Authctxt *authctxt); 160 #endif /* KRB5 */ 161 162 #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) 163 #include <shadow.h> 164 int auth_shadow_acctexpired(struct spwd *); 165 int auth_shadow_pwexpired(Authctxt *); 166 #endif 167 168 #include "auth-pam.h" 169 #include "audit.h" 170 void remove_kbdint_device(const char *); 171 172 void do_authentication2(struct ssh *); 173 174 void auth_log(struct ssh *, int, int, const char *, const char *); 175 void auth_maxtries_exceeded(struct ssh *) __attribute__((noreturn)); 176 void userauth_finish(struct ssh *, int, const char *, const char *); 177 int auth_root_allowed(struct ssh *, const char *); 178 179 char *auth2_read_banner(void); 180 int auth2_methods_valid(const char *, int); 181 int auth2_update_methods_lists(Authctxt *, const char *, const char *); 182 int auth2_setup_methods_lists(Authctxt *); 183 int auth2_method_allowed(Authctxt *, const char *, const char *); 184 185 void privsep_challenge_enable(void); 186 187 int auth2_challenge(struct ssh *, char *); 188 void auth2_challenge_stop(struct ssh *); 189 int bsdauth_query(void *, char **, char **, u_int *, char ***, u_int **); 190 int bsdauth_respond(void *, u_int, char **); 191 192 int allowed_user(struct ssh *, struct passwd *); 193 struct passwd * getpwnamallow(struct ssh *, const char *user); 194 195 char *expand_authorized_keys(const char *, struct passwd *pw); 196 char *authorized_principals_file(struct passwd *); 197 198 int auth_key_is_revoked(struct sshkey *); 199 200 const char *auth_get_canonical_hostname(struct ssh *, int); 201 202 HostStatus 203 check_key_in_hostfiles(struct passwd *, struct sshkey *, const char *, 204 const char *, const char *); 205 206 /* hostkey handling */ 207 struct sshkey *get_hostkey_by_index(int); 208 struct sshkey *get_hostkey_public_by_index(int, struct ssh *); 209 struct sshkey *get_hostkey_public_by_type(int, int, struct ssh *); 210 struct sshkey *get_hostkey_private_by_type(int, int, struct ssh *); 211 int get_hostkey_index(struct sshkey *, int, struct ssh *); 212 int sshd_hostkey_sign(struct ssh *, struct sshkey *, struct sshkey *, 213 u_char **, size_t *, const u_char *, size_t, const char *); 214 215 /* Key / cert options linkage to auth layer */ 216 int auth_activate_options(struct ssh *, struct sshauthopt *); 217 void auth_restrict_session(struct ssh *); 218 void auth_log_authopts(const char *, const struct sshauthopt *, int); 219 220 /* debug messages during authentication */ 221 void auth_debug_add(const char *fmt,...) 222 __attribute__((format(printf, 1, 2))); 223 void auth_debug_send(struct ssh *); 224 void auth_debug_reset(void); 225 226 struct passwd *fakepw(void); 227 228 /* auth2-pubkeyfile.c */ 229 int auth_authorise_keyopts(struct passwd *, struct sshauthopt *, int, 230 const char *, const char *, const char *); 231 int auth_check_principals_line(char *, const struct sshkey_cert *, 232 const char *, struct sshauthopt **); 233 int auth_process_principals(FILE *, const char *, 234 const struct sshkey_cert *, struct sshauthopt **); 235 int auth_check_authkey_line(struct passwd *, struct sshkey *, 236 char *, const char *, const char *, const char *, struct sshauthopt **); 237 int auth_check_authkeys_file(struct passwd *, FILE *, char *, 238 struct sshkey *, const char *, const char *, struct sshauthopt **); 239 FILE *auth_openkeyfile(const char *, struct passwd *, int); 240 FILE *auth_openprincipals(const char *, struct passwd *, int); 241 242 int sys_auth_passwd(struct ssh *, const char *); 243 244 #if defined(KRB5) && !defined(HEIMDAL) 245 krb5_error_code ssh_krb5_cc_gen(krb5_context, krb5_ccache *); 246 #endif 247 248 #endif /* AUTH_H */ 249